Herein, related art is discussed to provide a context for the present invention. Related art labeled “prior art” is admitted prior art; related art not labeled “prior art” is not admitted prior art.
Many commercial and other enterprises use storage area networks (SANs) for distributing, acquiring, and managing vast quantities of data. A SAN is a network in which one or more host servers access one or more storage units such as hard disks, optical disks, and tape drives. Typically, each host server includes one or more host-bus adapters (HBAs), each with one or more physical ports.
Large SANs tend to employ virtualization on many levels to allow flexible configuration and reconfiguration of hardware resources. Virtual servers can be used so that a single server can emulate several smaller servers, each with its own instance of an operating system. Disk arrays are divided into logical units (LUNs) that can service different host adapter ports (from the same or different physical servers). Multiple virtual HBA ports can be assigned to a physical port and used so that different virtual servers (running on the same server) can have exclusive access to different sets of LUNs using that same physical HBA port.
Security is a general concern for many computing environments and an issue for enterprise-scale computing environments. LUN masking contributes to security by making LUNs discoverable and useable by specified physical ports and no others. More recently, this approach has been extended so that different virtual servers on the same platform (physical server or physical partition of a server) can be assigned different virtual ports, with LUNs being assigned mutually exclusively to ports, whether physical or virtual.
For a virtual server to migrate to and access its LUNs from a new host platform, the original virtual-port assignment for the initial platform's LUNs may have to be cancelled to allow a new virtual-port assignment for the LUNs associated with the new hosting platform's HBA ports. This reassignment can be time consuming and error-prone as virtual-server utility programs may have to be informed of the change in virtual port name. Alternatively, the LUNs can be configured to be accessible from different physical ports, but this can compromise security.